This invention relates to a power transmission device and more particularly to an improved combination torsional and vibration damper for the power transmission system of an engine in an application such as in an outboard motor.
In conjunction with the propulsion of devices by means of internal combustion engines, it is oftentimes the practice to employ a flexible coupling in the drive from the engine to the propulsion device so as to absorb torque fluctuations as are inherent in the operation of internal combustion engines. In addition, it is also desirable to employ a torsional vibration damper in the engine so as to absorb torsional vibrations. The torsional vibration damper should be positioned in the drive train at a location other than a node of the torsional vibrations in order to assure good damping. In addition, the flexible coupling should also be located in a position where the torque variations can be effectively dampened. In many types of applications, this locating of the elements provides no problems due to the relatively long length of the drive train and the substantial dimensions of the associated unit being propelled.
In conjunction with outboard motors and marine outboard drives, however, the provision of the two separate elements at different locations can be quite a problem. Specifically, the compact configuration of a marine outboard drive makes it very difficult to employ two such devices in the drive train at the appropriate locations.
It is, therefore, a principal object of this invention to provide a combined torsional and vibration damping coupling for a power transmission.
It is a still further object of this invention to provide an improved, compact, torsional and vibration damping coupling for a power transmission for applications such as in a marine outboard drive.